Aromatic carbonates are monomers useful for the preparation of polycarbonate and extensive studies have been conducted on developing preparation methods thereof. Aromatic carbonates are conventionally prepared by phosgenation of phenol and phosgene in the presence of an alkali. However, this method uses poisonous phosgene and a neutral salt generated as a by-product must be treated.
In order to solve such disadvantages, transesterification of phenol and aliphatic carbonate such as dimethyl carbonate to produce aromatic carbonate has been developed. The transesterification is generally conducted in the presence of a catalyst, for example, PbO, TiX4 (X=alkoxy or aryloxy group), SnR2(OPh)2 (R=alkyl group), and the like. PbO has high stability but low catalytic activity, resulting in a significantly low reaction rate. TiX4 and SnR2(OPh)2 have a higher activity than PbO, but have inadequate stability and generate a substantial amount of ether as a by-product.
Further, a method of preparing aromatic carbonate through carbonylation of an aromatic hydroxyl compound using carbon monoxide and oxygen has been developed. However, since such synthesis using carbon monoxide as a reactant has a remarkably low reactivity and requires a high-pressure reactor, it has limited commercialization potential.
Thus, there is a need for a method for stably preparing aromatic carbonate with high yields using dialkyl carbonate as an initial material instead of carbon monoxide.